Process of forming silver transfer images

ABSTRACT

A process for the production of silver images according to the silver complex diffusion transfer process carried out in the presence of a hydroxylamine derivative developing agent and a (poly)amino(poly)carboxylic acid sequestering agent in acid form or in the form of a water-soluble salt is described. Better quality transfer images at substantially lower illumination levels are realized.

United States Patent [191 Thiers et al.

PROCESS OF FORMING SILVER TRANSFER IMAGES Inventors: Robrecht Julius Thiers, Brasschaat; Josef Frans Willems, Urbijk; Roger Alois Spriet, Edegem, all of Belgium Assignee: Gevaert-Agfa N.V.,' Mortsel, Germany Filed: Oct. 12, 1970 Appl. No.: 80,151

Foreign Application Priority Data Oct. 27, 1969 Great Britain 52,57l/69 US. Cl. 96/29 R Int. Cl. ..G03c 5/54 Field of Search .L ..96/29, 76

[ Feb. 13, 1973 [56] References Cited UNITED STATES PATENTS 3,189,454 6/1965 Luckey et al ..96/95 3,458,316 7/ l 969 Viro ..96/94 Primary Examiner-J. Travis Brown Assistant Examiner-John L. Goodrow Attorney-Brufsky, Staas, Breiner and Halsey [57] ABSTRACT 12 Claims, No Drawings PROCESS OF FORMING SILVER TRANSFER IMAGES The present invention relates to the formation of silver images by the silver complex diffusion transfer process.

Processes for forming silver images by the steps of image-wise exposure and development of a photosensitive silver halide element, the formation of a diffusible complex of unexposed-silver halide in the unexposed areas of the said photosensitive element and the transfer by diffusion of said complex to an element, in superposed relationship with the photosensitive elemerit, where the silver of said complex is precipitated image-wise exposure of the photosensitive element,

which comprises a silver halide emulsion layer, the superposed elements i.'e., the photosensitive element and the image-receiving element are guided between a pair of pressure rollers whereby the viscous processing liquid is spread as a uniform layer between the photosensitive element and the image-receiving element.

The photosensitive element and the image-receiving element are maintained in superposed relation for a determined period, usually of the order of 10 to 120 seconds, during which the exposed. silver halide is developed, the undeveloped silver halide is converted into a water-soluble complex silver salt and the said complex is transferred through the layer of processing liquid to the silver precipitating layer of the imagedevelopment activity is higher than that of the N,N-dialkylhydroxylamines include for example aminoalkylhydroxylamines, more especially N,N-dialkylhydroxylamines having in at least one of the N-alkyl groups an intralinear amino nitrogen atom, either cyclic or acyclic, examples of which can be found in US. Pat. No. 3,287,125, of Milton Green, Adnan A. Sayigh and Henri Ulrich, issued Nov. 22, l966, alkoxy hydroxylamines, more especially N,N-dialkyl hydroxylamines of which. at least one of the N-alkyl groups is substituted by alkoxy or alkoxy-alkoxy,-examples of which can be found in U.S. Pat. No. 3,293,034 of Milton Green, Adnan A. Sayigh and Henri Ulrich, issued Dec. 20, 1966 and sulphone hydroxylamines, more especially N,N-dialkyl hydroxylamines having in at least one of the N-alkyl groups an intralinear sulphonyl SO group, examples of which can be found in US.

Pat. No. 3,287,124 of-Milton Green, Adnan A. Sayigh and Henri Ulrich, issued Nov. 22, 1966.

It has now been found when using, in a process for the production of silver images according to the silver complex diffusion transfer process, carried out developing agent, a photosensor element the presence of a hydroxylamine derivative as silverhalide emulsion comprising a silver halide emulsion layer, and a (poly)amino(poly)carboxylic acid sequestering compound, in acid form or in the form of a water-soluble salt, transfer images are obtained of improved quality.

The. {use of (poly)amino(poly)carboxylic acid sequestering compounds, in acid form or in the form of a water-soluble salt, in a silver. complex diffusion transfer process wherein use is made of a hydroxylamine developing agent is effective to give better quality transfer imagesat substantially lower illumination levels than are necessary in the absence of said compounds, without giving rise to a noteworthy decrease in maximum density of the images formed.

Therefore, in accordance with the present invention,

there is provided a process of forming silver transfer -images which comprises the steps of exposing a receiving element where it is converted into a visible print. At the end of this contact period the photosensitive element is separated by stripping from the imagereceiving element. Elements suitable for use in this 1 silver complex diffusion transfer process are described in detail e.g., in US. Pat. No. 2,543,181 of Edwin H. Land, issued Feb. 27, 1951.

A wide variety of silver halide developing agents and silver halide complexing agents, are known for use in such diffusion transfer processes.

As silver halide developing agents it has been proposed amongst others in US. Pat. No. 2,857,276 of Edwin H. Land and Helen J. Tracy, issued Oct. 21, 1958 to use hydroxylamine and derivatives thereof, of which the oxidation products leave no residual stain in the positive silver image obtained. Hydroxylamine itself is less suitable because it gives rise to fog but the N,N-

dialkylhydroxylamines such as N,N-'diethylhydroxylamine and the heterocyclic N-hydroxylamines such as N-hyd roxymorpholine, N-hydroxypiperidine and N- hydroxypyrrolidine disclosed in the above US. Pat specification are particularly suitable. Other hydroxylamine derivatives that have been-proposed for use as silver halide developing agents and of which the photosensitive element containing a silver halide emulsion layer and a (poly)amino(poly) carboxylic acid sequestering compound, in acid form or in the form of a water-soluble salt, developing the exposed photosensitive silver halide emulsion layer and forming a soluble silver complex of unexposed silver halide by treating the said photosensitive silverhalide emulsion layer with an alkaline processing fluid in the presence of a hydroxylamine developing agent and a silver halide complexing agent, transferring said soluble silver complex by diffusion to the silver receptive layer of an imagereceiving element in superposed relationship with said silver halide emulsion, forming at said silver receptive layer' an image incorporating silver from said silver complex, and separating said image-receiving element from said photosensitive element.

Examples of suitable (poly )amino(poly)carboxylic acid sequestering compounds as well as details about the preparation of said sequestering compounds can be found in Ind.Chim.Belg. Tome XXI (1956) p. 338-346 and in Ind.Chirn.Belg. Tome XXIII (1958). p. l,l05l,l15.

Particularly suitable (poly)amino(poly)carboxylic acids for use in acid or salt form in accordance with the present invention can be represented by the following non-limitative general formula:

wherein:

' L stands for alkylene including substituted alkylene e.g., hydroxyalkylene, cycloalkylene including substituted cycloalkylene or alkylene interrupted by one or more hetero atoms, such as an oxygen atom,

x represents 0, l or 2,

R stands for lower alkylenee.g.,- methylene and ethylene including substituted lower alkylene e.g., alkylene substituted by alkyl, aryl, aralkyl, including substituted alkyl, aryl and aralkyl, and

each of R and R (the same or different) stands for hydrogen, lower alkyl including substituted lower alkyl, aralkylincluding substituted aralkyl or aryl including substituted aryl; examples of substituted alkyl groups for R and for R are'alkyl substituted with hydroxyl, halogen, alkoxy, carbamoyl, amino, substituted amino e.g., v dihydroxyalkylamino,

- epoxy, carboxyl, sulpho, phosphono, mercapto, alkylmercapto, alkoxycar'bonyl, a nitrogen-containing heterocyclic ring, e.g., pyridyl and examples of substituted aryl groups and aralkyl groups for R, and/or R are: aryl and aralkyl substituted by hydroxyl, halogen, alkyl, alkoxy, nitro, carboxyl and sulpho.

The following is av non-limitative list of examples of (poly)amino(poly)carboxylie acids corresponding to the above general formula:

1. NaOOCH2C CHz-COONa N-,CHz CHz-N HOOC-H2C CH2COOH ethylenediamine,N,N,N,N-tetraacetic acid disodium salt 2. Hood-mo CH2-COOH u-on-c Hr-N IIOOC-H:C CH CHz-COOH 1,2-pr0pylenediamine,N,N,N,N-tctraacetic acid N-(2-hydroxypropyl)-cthylencdiamlne,N,N-triacctic acid 'no-cnribon cu -coon N-(2,3-dihydroxypropy1)-cthy1enediamine ,N,N ,N-triacetlc acid N-(2-hydroxyetliyl)-N(a-pyridinomcthyl)ethylene dianiinc-N, N-diacetic acid s. nooc uzc curcoon How-mo om-om-0n N-(Z-hydroxyetliyl)-N-phosphonomctliyl-othylenediamine, N, N -diacetic acid 11000-1120 CHz-(JOOH N-(2, 3-dihydroxypropyD-N"(2-sulphoethy1)-cthyleuediamine, N, N'-diacctic acid N, N-di(2-hydroxycthyl)cthylefictriamine, N, N, Nf-triacctic aei N-(3,fi-dichloroi-hydroxy-benzyl)-N'-(2-hydroxy-ethyl)ethylenediamine,

N,N-diaeetie acid 2-hydroxy-3,5-dichl0rohenzylamino-N-acetiu acid sodium salt.

In a process forpreparing silver transfer images according to the present invention wherein compounds corresponding to the above general formula are used, the said compounds are presentin the photosensitive element. These compounds may be located in the silver halide emulsion layer of said element .or in a layer in bromoiodide, silver chloroiodide, silver chlorobromide, silver chlorobromoiodide, etc. These silver halide emulsions can contain spectral sensitizers, speedincreasing addenda, hardeners, coating aids, antifoggants, plasticizers and the like conventional emulsion addenda.

The photosensitive silver .halide element may also comprise in the silver halide emulsion layer or in a layer in water-permeable relationship with the said emulsion .layer, compounds having a favorable effect on the maximum density of the image formed and/or in the speed of the photosensitive element. Examples of these compounds are the l-aryl-3-pyrazolidinone compounds ex-. amples of which can be found in the application for Silver Complex Diffusion Transfer Process filed on even date herewith United Kingdom Patent applica-' tionNo. 52,572/69), as well as diamine or polyamine' compounds and mor'pholine derivatives, typical examples of which are the compounds represented bythe following formulas:

OH I CH3 O HQC CH2 Ha (JIIz'IICl As previously noted, processing occurs with an alkaline processing liquid in the presence of a silver halide complexing agent and a hydroxylamine developing m0 CH; on on on .agent. These agents are preferably present in the processing liquid itself although it is also possible to incorporate them in the photosensitive or image-receiving element. For instance, the hydroxylamine derivatives can be incorporated in the said elements in the form of acid salts thereof e.g., in hydrochloride or hydrobromide form. When the developing and/or silver complexing agents are incorporated in the photosensitive and/or image-receiving element, the development of the exposed silver halide and the formation of the silver complex of unexposed silver halide is activated whenthe alkaline processing fluid is spread as a thin layer between the photosensitive element and the image-receiving element.

Silver halide complexing agents suitable for use in diffusion transfer processes are well known in the art and include alkali metal thiosulphates and thiocyanates, such as sodium thiosulphate and sodium thiocyanate. Silver halide complexing agents that are particularly suitable for use in accordance with the present invention are cyclic imides for example barbituric acid, uracil and urazole as well as derivatives thereof, examples of which can be found in US. Pat. No. 2,857,276 mentioned above. Among the hydroxylamine developing agents that are particularly suitable, mention may be made of the heterocyclic N-hydroxylamines such as N-hydroxymorpholine, N-hydroxy piperidine and N- hydroxy pyrrolidine, the primary and secondary N- lower alkyl hydroxylamines such as N,N-diethylhydroxylamine, the alkoxy-substituted derivatives thereof such as N,N-di(2-ethoxyethyl) hydroxylamine and N- ethyl-N-(2-ethoxyethyl)-hydroxylamine, the sulphonehydroxylamines such as N-m'ethyl-N-2-ethylsulphonylethyl hydroxylamine and bis-2-(methyl-hydroxylamino)-ethyl sulphone and the aminoalkyl hydroxylamines such as N-methyl-N-2-dirnethylaminoethylhydroxylamine. Further examples of such hydroxylamine derivatives can be found in'the US. patent specifications referred to above. I

The processing fluid comprises bases imparting to the fluid the required alkalinity. As examples of such bases mention may be made of alkali-metal hydroxides, e.g., sodium and potassium hydroxide, sodium carbonate, borax, sodium metaborate, trisodium phosphate, etc.

I The fluid may further contain, or dissolve in its travel to the photosensitive element, other compounds which plastic so that when the liquid isremoved from the processing layer by absorption and/or evaporation there remains a solid plastic film. The .film-forming plastic may be any-of the high molecular weight polymers which are stable to alkali and which are soluble in aqueous alkaline solutions e.g.,' hydroxyethylcellulose, starch or gum, polyvinylalcohol, the sodium salts of polymethacrylic acid and polyacrylic acid, sodi-. um alginate, sodium carboxymethyl cellulose. As is known in the art, stripping of the silver halide element from the image-receiving element may separate the solidified layer of processing composition from the image-receiving element or may permit the layer of processing composition to remain in contact withthe image-receiving element so that the solidified layer provides a protective coating over the image obtained.

The viscous processing fluid for use in in-camera processing is preferably confined within a hermetically sealed container or pod which is positioned between the p otosensitive element and the image-receiving element and which is ruptured and releases its contents receptive element'between a pair of pressure-rollers. Such a container is impervious to the processing'liquid and to the vapor of said liquidQand may be formed of a multilayer composite material comprising as inner layer in contact with the liquid, a material which is impervious to the liquid as intermediate layer a substance which is impervious to the vapor of said liquid and as outer layer a material merely serving as a backing or support. In its preferred form, the container is formed of a multilayer material whose inner layer is formed of a plastic such as polyvinyl acetal e.g., polyvinyl butyral, polymeric esters such as cellulose acetate, cellulose acetate butyrate, polyvinyl acetate, polyvinyl chloride, etc. said layer being backed by a metal foil e.g., a lead foil or lead-tin foil which is impervious to the vapors of upon advancing the photosensitive element and imagesaid solution. The containers may be strengthened by a more rapid backing material such as kraft paper or a plastic such as polyvinyl acetate and polyvinyl chloride; More details as to the construction of such a ru'pturable container can be found amongst others in US. Pat. No. 2,634,886 of Edwin H. Land, issued Apr. 14, 1953.

The silver halide emulsion layer and/or the imagereceiving layer may be coated on opaque'or transparent supports. ln this way it is possible to exposethe photosensitive element from either side as desired and it is possible to form either reflection prints or transparencies.

The image-receiving layer of the image-receiving element preferably comprisesmentioned, promoting precipitation of the silver from the transferred silver complex. Examples of such agents, called development nuclei or shortly nuclei, are'well known andinclude sulphides, selenides, polysulph'ides, polyselenides, thioureas, thioacetamides, mercaptans, stannous halides, heavy metals or their salts and fogged silver halide. Sulphides of heavy metals'such as of antimony,

ill

bismuth, cadmium, cobalt, lead, nickel and silver are also suited. Lead sulphide and zinc sulphide as well as the complex salts thereof are especially effective either in themselves or mixed with thioacetamide, dithiobiuret and dithio-oxamide. Among the heavy metals silver,

gold, platinum, palladium and mercury are to be mentioned preferably in colloidal form.

The development nuclei may be associatedwith a granular, inorganic, water-soluble, substantially chemically inert substance such as silica as vehicle for the said nuclei whereby aggregation of the precipitated silver is promoted.

In at least one layer of the image-receiving elementother substances may also be incorporated which play a part in the formation of the diffusion transferimage e.g., black-toning agents, anti-yellowing agents, optical bleaching agents, softening agents, etc.

For in-camera processing the image-receiving element may be constructed as described in US. Pat. No. 2,823,] l2'of Edwin H. Land, issued Feb. ll, 1958. According to this United States patent specification the print-receiving element is so constructed that the viscous'processing fluid separates therefrom and leaves no droplets or film of developing composition on the print-receiving layer. The image-receiving layer is thin, holding a mass of water so small that there is not tactual wetness.'Moreover, by making the print-receiving layer so thin the tendency to curl is also avoided. Consequently, when peeled from the photosensitive element, which carries the viscous processing layer, the image-receiving element appears to be a dry sheet.

According to this United States patent specification a layer, which is substantially impervious to the processing liquid and which may be the liquid-impervious surface of a supporting sheet which is entirely formed of liquid-impervious material is provided between the silver precipitating layer in which the positive is formed, and the remainder of the image-receiving element. Further, the image-receiving layer is provided with a surface from which the viscous film of processing fluid may be readily stripped. Thus, according to said United States patent specification theouter surface of the image-receiving element contacting the layer of processing composition is so constituted as to have a lesser adhesion for the solid residue of the liquid processing composition than does the photosensitive element. As a result, the photosensitive. element, when stripped from the image-receiving element, carries with it the residue of the processing composition. Further, between the image-receiving layer and the stripping layer an abrasion resistant coating may be provided.

According to this United States patent specification stripping of the silver halide element from the image- 'receiving element separates the layer of processing solution from the image-receiving element. However,

as noted hereinbefore in order to provide the image- EXAMPLE 1 A photosensitive element was prepared which com- 200 mg of prises a silver bromoiodide emulsion layer applied to a paper support and containing per kg an amount of silver halide corresponding to 60 g of silver nitrate and. a (poly)amino(poly)carboxylic acid compound as listed in the table below in the amount given. After exposure, the photosensitive element together with an image-receiving element comprising a silver receptive layer containing development nuclei dispersed in a matrix of colloidal silica coated on a water-impervious base according to the practice described in U.S. Pat. No. 2,823,122 of Edwin 1-1.Land,issued Feb. 11,1958, were advanced in superposed relationship between a pair of pressure applying rollers to spread between them in a thin layer a processing composition comprisingper liter:

sodium carboxymethyl cellulose 40 g sodium hydroxide 35 g uracil 75'g N,Nxli(2-.eth oxyethyl)- hydroxylamine 40 ml After. a' contact period of 36 seconds, the emulsion together with the layer of processing liquid was These results show that the compounds of use according to the present invention have a favorable effect I on the speed without causing a noteworthy decrease in maximum density of the image formed.

EXAMPLE 2 Example 1 was repeated with the difference that the photosensitive elements were processed directly after 7 preparation and afterhaving been stored for days at 45C and 15 percent of relative humidity.

The following results were attained.

Fresh material Stored material Compound added per kg of emulsion D D Gam- Speed D,,, Gam- Speed m ma none 1.57 0.03 1.73 100 1.59 0.03 1.63 87 50 mg of compound 10 1.53 0.03 1.33 139 1.58 0.03 1.47 112 100 mg of compound 10 1.56 0.03 1.50 136 1.51 0.03 1.11 127 200 mg of compound 10 1.54 0.02 1157 136 1.48 0.03 1.21 130 .50 mg of compound 12 1.55 0.03 2.03 136 1.56 0.03 1.40 115 100 mg of compound 12 1.54 0.03 1.46 '118 compound 12. 1.54 0.03 1.49 139 1.50 0.03 1.24 127 50 mg of compound 15 1.56 0.02 1.82 121 1.59 0.04 1.59 106 100mg of compound 15 1.55 0.03 1.70 136 1.58 0.04 1.55 109 200 mg of compound 15 1.55 0.03 1.51 136 1.55 0.03 1.40 121 EXAMPLE 3 Example 1 was repeated with the difference that the silver halide emulsion layer of the photosensitive ele ment now comprises compound 24 in an amount of 1 g per kgof emulsion. The sensitometric results obtained, as compared with the results obtained when no compound 24 is present are the following: 1

This example is analogous to example 3 with the only difference that the silver halide emulsion contains per kg in addition to 1 g ofc ompound 24, 0.5 g of 1'-phenyl- 3-pyranzolidinone.

- The following results were attained.

Material stored for 5 days Material Fresh material 1).}. Cam Speed D Gam- S eed I Comparison material Material comprising compound 24 and 0.5

g of l-phenyl- -Py razohdinone Material comprising 0.5 g of l-phenyl-3- pyrazolidinone and no compound 24 When comparing these results with the results obtained in example 3 it appears that l-phenyl-3- pyrazolidinone has a favorable effect on the maximum density of the image formed and that the gain in speed by the presence of compound 24 is maintained though.

1 -pheny1-3-pyrazolidone when usedalone has a marked desensitizing effect after storage.

EXAMPLE 5 This example is analogous to Example 1. The photosensltlve element accordingto the invention now comprises in the silver halide emulsion layer 500 mg of compound 1 per kg of emulsion.

The following results were attained.

Material Stored for 5 da s at 49C 15 Material Fresh material 0..., Gam- Speed is.;,e.....- Speed I mruma Comparison material L58 0.05 L49 I 1.62 0.04 1.95 73 Material comprisin 500 mgo compound l L55 0.03 1.43 I40 .l.55 0.03 L45 l4l approximately percent).

EXAMPLE 8 From Example 5 it appears that compound 1 has a favorable effect on the sensitivity without having a noteworthy influence on the maximum density of the image formed.

The results below show that when per kg of emulsion an amine is added in the amount given in. the table below, in addition to 500 mg of compound l,'the speed can still be increasedby approximately percent.

. Speed Compound added per kg of emulsion Dun: Dmin- Gamma percent -500 mgsol compound 1 1. 59 0. 04 I. 34 100 500 mg. of compound 1 plus 100 mg. of Hg1N-CHgCH1NHCH1CHgOH 1. 55 0. 04 l. 04 126 500 mg. at compound 1 plus 100 mg. of H N C H-CH-CH-NH1 1. 54 0.05 1.10 a 126- NH: v 1.55 0.0E 1.00 123 500 mg. of compound 1 plu 100 mg. of HiN (OH,); i H-C 0 0H-2H Cl 1. 55 0. 05 1.00 123 Material Fresh material G m- Speed ma (k) D 3 comparison matenal comprising 500 mg of compound 1 material comprising 500 mg of compound. 1 and 100 mg of the 3-pyrazolidinone compound I Y 40 L35 0.03 l.l7l29 1.42 0.03 l.l4 75 EXAMPLE 7 Example 6 'is repeated with the difference that now per kg of emulsion 2 g of l-phenyl-4,4-dimethyl-5- ethoxy-3-pyrazolidinone is used instead of 100 mg of lp-tolyl-4,4-dimethyl-5-ethoxy-3-pyrazolidinone.

The following results were attained with fresh material. v

Material D,,,, D Gamma Speed(%) Comparison material comprising 500 mg of compound 1 material comprising 500 mg of compound l and 2 g of the 3- pyrazolidinone compound These results also prove that the speed can still be further increased by 40 percent by adding to the emulsion in'addition to the (poly)amino(poly)carboxylic acid a compound as described and claimed in United Kingdom Patent application 52,572/69, the maximum density of the image formed also being increased (by We claim: a 1. in a process of forming'silver transfer images which comprises the steps of image-wise exposing a photosensitive element containing a silver halide emulsion layer, developing the exposed silverhalide and forming a soluble silvercomplex of unexposed silver halide by treating the said silver halide emulsion layer with an alkaline processing liquid in the presence of a hydroxylamine developing agent and a silver halide complexing agent, transferring said solublesilver complex-by diffusion to an image-receiving elementin Superposed relationship with said photosensitive element, forming at an image-receiving layer of said imagereceiving element an image incorporating silver from said silver complex, and separating said image-receiving element from said photosensitive element, the use of a photosensitive element which includes in the silver halide emulsion layer or a hydrophilic colloid layer in water-permeable relationship with the said emulsion layer a (poly)amino(poly)carboxylic acid compound inthe acidform or in the form of a water-soluble salt.

2. A process according to claim 1, wherein said (poly)amino(poly)carboxylic acid corresponds to the formula:

wherein: I

L stands for an alkylene group, a cycloalkylene group, or an alkylene group interrupted by one or more hetero atoms,

x represents 0, l or 2,

R stands for a lower alkylene group, and

each of R and R (the same or different) stands for 1 hydrogen, a lower alkyl group,,an aralkyl group or an aryl group.

3. A process according to claim 1, wherein the said silver halide complexing agent is a cyclicimide.

4. A process accordingto claim 3, wherein the said cyclic imideis uracil. 5. A process according to claim 1, wherein the (poly)amino(poly)carboxylic acid compound is v salt.

present in the silver halide emulsion layer of the photosensitive element in an amount of from about 30 mg to 15 gper mole of silver halide.

6. A process according toclaim 1, wherein said photosensitive element also includes an l-aryl-3- pyrazolidinon'e compound.

7. A process according to claim 1, wherein said photosensitive element also includes a diamine or polyamine compound.

8. The process according to claim 1 wherein said (poly)am ino(poly)carboxylic acid compound is ethylenediamine,N,N,N',N' tetraacetic acid disodium 9. The process according to claim 1 wherein said (poly)amino(poly)carboxylic acid compound is hydroxy-3,5 dichlorobenzylamino-Nacetic acid sodium salt. a i 

1. In a process of forming silver transfer images which comprises the steps of image-wise exposing a photosensitive element containing a silver halide emulsion layer, developing the exposed silver halide and forming a soluble silver complex of unexposed silver halide by treating the said silver halide emulsion layer with an alkaline processing liquid in the presence of a hydroxylamine developing agent and a silver halide complexing agent, transferring said soluble silver complex by diffusion to an image-receiving element in superposed relationship with said photosensitive element, forming at an image-receiving layer of said image-receiving element an image incorporating silver from said silver complex, and separating said image-receiving element from said photosensitive element, the use of a photosensitive element which includes in the silver halide emulsion layer or a hydrophilic colloid layer in water-permeable relationship with the said emulsion layer a (poly)amino(poly)carboxylic acid compound in the acid form or in the form of a water-soluble salt.
 2. A process according to claim 1, wherein said (poly)amino(poly)carboxylic acid corresponds to the formula:
 3. A process according to claim 1, wherein the said silver halide complexing agent is a cyclic imide.
 4. A process according to claim 3, wherein the said cyclic imide is uracil.
 5. A process according to claim 1, wherein the (poly)amino(poly)carboxylic acid compound is present in the silver halide emulsion layer of the photosensitive element in an amount of from about 30 mg to 15 g per mole of silver halide.
 6. A process according to claim 1, wherein said photosensitive element also includes an 1-aryl-3-pyrazolidinone compound.
 7. A process according to claim 1, wherein said photosensitive element also includes a diamine or polyamine compound.
 8. The process according to claim 1 wherein said (poly)amino(poly)carboxylic acid compound is ethylenediamine,N,N, N'',N''-tetraacetic acid disodium salt.
 9. The process according to claim 1 wherein said (poly)amino(poly)carboxylic acid compound is ethylenediamine,N, N''-di(o-hydroxyphenyl acetic acid).
 10. The process according to claim 1 wherein said (poly)amino(poly)carboxylic acid compound is 2-hydroxyethyl-amino diacetic acid.
 11. The process according to claim 1 wherein said (poly)amino(poly)carboxylic acid compound is ethyleneglycol bis(2-aminoethyl)-N,N,N'',N''-tetraacetic acid. 